1. Field of the Invention
The present invention is an air gap or air gap apparatus particularly adapted in one embodiment to vent the waste water discharge from a source such as a household dishwasher, and to simultaneously vent the waste water discharge from a reverse osmosis system.
2. Description of the Prior Art
Most plumbing codes specify that an anti-siphon or air gap be provided for venting the waste water discharge from sources such as a dishwasher. The codes typically specify that the air gap be located between the dishwasher outlet hose and the household sewage drain, or between the outlet hose and the garbage disposer if one is provided. In operation, the air gap prevents development of a vacuum that might cause waste water to be siphoned back into the dishwasher and eventually contaminate the household water supply system. This can occur when residual water in the bottom or pump portion of the dishwasher finds it way back into the water supply system.
The body of such an air gap is typically mounted to the upper surface of the rear mounting ledge of the sink top or to the upper surface of a kitchen counter next to the sink.
One or more openings in the air gap body provide communication between atmosphere and a vent chamber of the body. Since the dishwasher outlet hose communicates with an inlet to the vent chamber, the stream of waste water passing through the chamber is vented to atmosphere.
To comply with typical plumbing codes, a system which includes both a dishwasher and a reverse osmosis (RO) unit must also vent the RO discharge to prevent back siphoning of that discharge and possible contamination of the household water supply.
Installing a second, independent air gap solely for the RO system would be time consuming, expensive and unsightly because this typically requires that another hole be provided in the sink or counter top, which could cause splitting or cracking of those components. A second air gap usually also requires further modification of the existing plumbing.
For the foregoing reasons either a multipurpose air gap is needed which can be quickly and easily installed to vent both the dishwasher and the RO system, or an air gap retrofit kit is need to modify the existing air gap so that it vents more than one source of waste water.
My U.S. Pat. No. 5,713,385 (Air Gap Body For Reverse Osmosis System), issued Feb. 3, 1998, is illustrative of one means of meeting this need. The present invention is an improvement over the systems of the prior art, including that disclosed in the ""385 patent.
According to the present invention, the RO drain conduit or tube is connected to the existing dishwasher air gap in a manner such that the RO drain flow is also routed through the air gap body without having to dismount it, or disturb the existing plumbing connections, or make any changes visible from above the sink or counter top. As will be seen, the modified air gap also gives the homeowner a choice between using the existing decorative cap on the air gap body or substituting a new one.
Another important feature of the present invention is that a dual purpose air gap can be installed in a new home just as easily and as inexpensively as existing air gaps, or a retrofit kit can be employed in older homes to convert its old style single purpose air gap to a dual purpose air gap.
The present air gap body is particularly adapted for rapid and easy connection to existing RO drain tubing by utilizing well known xe2x80x9cpush-onxe2x80x9d connectors or couplers to couple the tubing to either of the popular xe2x85x9c or xc2xc inch outer diameter polyethylene drain tubing.
Thus, in accordance with the present invention, an existing dishwasher air gap body can be modified or retrofitted to simultaneously vent multiple waste water sources, such as a dishwasher and an RO system, or a new air gap body can be installed to perform these functions without further modification.
The air gap housing or body used comprises a molded, relatively hard plastic housing having an elongated and cylindrical central housing. An upper housing is threaded onto the upper end of the central housing and mounts a cap portion operative to downwardly direct the upwardly flowing waste water coming into the air gap body.
The air gap body also includes a bifurcated lower housing having a smaller diameter inlet conduit or port for receiving the dishwasher waste water, and a larger diameter outlet conduit or port for discharging the waste water to a household garbage disposer, if one is installed, or directly to the sink drain piping if there is no disposer. The foregoing structure is generally known in the prior art.
The upper housing of the air gap body includes external male threads having an approximate outside diameter of 1 xc2xc inches, which is at least xe2x85x9 inch smaller than the typical 1 xe2x85x9c inch diameter mounting hole provided to receive the air gap body. This space or clearance is enough to enable an RO drain tube having an outside diameter of about xe2x85x9 inch to pass upwardly into venting spaces in the air gap body for venting to atmosphere.
Use of the clearance space eliminates any need for another hole in the sink to route the RO waste water into the vented spaces. It also eliminates any need for disconnecting or rearranging any of the existing conduit connections.
According to the present invention, the existing upper nut or comparable element between the air gap housing and the upper sink surface is removed, and a special upper housing and trim ring are installed. The existing lower nut is backed off or threaded downwardly, and a special split or slotted spacer washer is placed between the lower nut and the undersurface of the sink. The split or slot in the spacer washer is large enough to allow one or more small conduits or tubes through the spacer, at least one of the tubes being the RO waste tube.
The RO waste tube is preferably made of a flexible, low friction material such as tetrafluoroethylene which can slip through small spaces. The tubing has a wall sufficiently thick that it can be curved or formed around small radii without kinking or collapsing and consequent obstruction of fluid flow.
The cap portion of the air gap body is threadably assembled onto the upper housing. It includes internal walls having deflecting surfaces which receive and downwardly direct the relatively high volume flow of dishwasher waste water that is flowing upwardly through the inlet port of the air gap body. The downwardly directed waste water passes into the upper part of the upper housing, from where it is vented to atmosphere through one or more vent openings in the cap portion and in a vent cap overlying the cap portion.
The waste tubing or conduits from the RO unit are frequently larger than the xe2x85x9 inch outside diameter RO waste tube used in the present invention. In such cases a specially designed one-piece tubing adapter is provided for connecting the smaller xe2x85x9 inch RO waste tube to different sizes of tubing, including the almost exclusively used xc2xc and xe2x85x9c inch sizes of tubing.
Installation of the present retrofit or modified air gap requires replacement of a minimum number of parts, all of which are readily accessible from above the sink. No substantial plumbing changes are required whatsoever.
Other objects and features of the present invention will become apparent from the following more detailed description taken in conjunction with the accompanying drawings.